The moment coffee is roasted, the process of ageing begins.
Carbon dioxide (CO2) is released, and many volatile organic compounds responsible for a coffee’s aroma and flavour degrade. Meanwhile, the fatty acids that contribute to its freshness start to oxidise.
Although there are a number of factors that influence the speed at which coffee ages, one of the most significant is temperature.
While green coffee beans require high temperatures to change from their raw form to a consumable good, too much heat after roasting can accelerate the movement of molecules in the beans, leading to a loss of freshness.
As a result, it’s important for roasters to understand the impact of different temperatures on their roasted coffee, not only to ensure it’s protected during storage, but also to inform their choice of packaging.
To find out more, I spoke with 2019 World Cup Tasters finalist and head of quality control at Bella Vista Coffee, Dulce Barrera.
What is the ideal storage temperature for roasted coffee?
Once coffee has been roasted, it usually spends at least some time in storage before being ground and brewed for consumption.
During this time, it’s important the coffee is stored at the correct temperature to preserve its freshness and reduce the chances of it becoming stale.
Dulce Barrera is three-time Guatemala Cup Tasters champion and head of quality control at Bella Vista Coffee. She explains that, ideally, coffee should be stored at room temperature immediately after roasting.
“I would say between 15°C and 26°C (59°F to 79°F),” she tells me. “Any higher can accelerate the speed at which coffee loses its aromatics and important flavour compounds.
“Having said that, low temperatures are better for maintaining the shelf life of the beans – but it can be expensive to store large quantities of coffee in these conditions.”
Indeed, studies show that freezing coffee keeps oxygen from entering it, therefore slowing its degassing rate and cellular activity. It can extend shelf life from three months to twelve.
During the summer months (or for those in hot countries), room temperature will often exceed the recommended maximum of 26°C.
As a result, roasters must ensure their coffee is protected from extreme heat or risk it becoming spoiled. This could mean moving it into a cool, dark environment, such as a cellar or refrigerator, or freezing where possible.
What’s the best coffee packaging for keeping out heat?
Roasters can go to great lengths to ensure their roasted coffee is protected from the effects of high temperatures. However, once it leaves the roastery and goes to the grocery store or consumer, the conditions in which the coffee is stored is out of their control.
This is where packaging comes in. High-quality packaging that can withstand temperature fluctuations and preserve the coffee’s freshness is essential.
If a customer buys a bag of coffee, only to get home and discover that it’s stale or “flat”, it could damage the reputation of the roastery irreparably.
But what are the best materials for keeping out heat? According to a paper on thermal-insulated bags and boxes, for packaging to be effective against high temperatures, it must offer resistance to the heat transfer by conduction, convection, and radiation.
Therefore, one of the best options for coffee is a PLA stand-up, multilayer pouch with aluminium lining.
The multiple layers provide sufficient thickness to protect against conduction, the small surface area of the stand-up pouch design protects against convection, and the aluminum foil helps to reflect radiation.
Furthermore, PLA can withstand temperatures as high as 216°C (420°F), with research suggesting it can keep a packaged item’s temperature low and stable for over a day in conditions ranging from 25°C to 30°C (77°F to 86°F).
As a bioplastic, PLA is also environmentally friendly. Not only does it require lower energy to manufacture compared to conventional plastics, it will fully decompose within 90 days providing it is taken to a commercial composting facility.
This is beneficial for roasters who want to protect their coffee while showcasing their commitment to sustainability.
However, it’s worth noting that the aluminium foil must be separated from the PLA before it goes to the facility. This is a complicated and expensive process that only a few local authorities offer.
Keeping customers informed
Although appropriate packaging is the one of the best defences against extreme temperatures, there are other steps you can take to preserve the freshness of your coffee once it leaves the roastery.
Dulce says that roasters should consider a roast-to-order business model to minimise the time between roasting and consuming. This is where coffee is only roasted when customers place an order, ensuring that it never spends more than a day or so in storage.
“To maintain the freshness of the coffee and protect the quality against heat, roasters should think about roasting smaller quantities of coffee more often,” she says. “That way, the coffee avoids long periods in storage or transit.”
Roasters should also educate their customers on how they can preserve the quality of their coffee once they buy it.
For example, Coffee Beans Delivered, a coffee delivery business in Queensland, Australia, advises customers to store their coffee in a cool, dark place with a stable temperature to protect it against the region’s typically hot and humid temperatures.
This information can be included on the side of the packaging or on a landing page accessed via a scannable QR code.
Preserving your coffee’s freshness in hot weather can be an uphill struggle. Not only does it require appropriate storage conditions in the roastery, it also relies on giving clear instructions to customers.
However, the right packaging supplier can make life a lot easier. At MTPak Coffee, we can help you design the perfect coffee bags to protect against the heat.
Our multilayer PLA packaging is fully customisable, which means you can include as much information as you want about how to correctly store the coffee once it leaves the roastery. We also use water-based inks and recyclable, BPA-free degassing valves, so that you can offer a completely sustainable product.